The Last Word On Nothing

I don’t remember where I heard this story. A mincey woman and her Very Small Dog were walking through an airport when the dog dropped a No. 2. The woman pulled a tissue out of her bag, crouched down… and wiped the dog’s butt. The twosome clacked off, leaving the little brown pile (and the tissue) to its fate.

Few people are that brazen. But the streets and parks of London speak for themselves: when no one’s looking, plenty of dog owners are abdicating their doody.

Not for long! If the borough of Barking gets its way, soon concerned citizens might start carrying little test tubes around to collect the lawn sausages. Barking wants to do “paternity tests” on street poo so they can send the dog’s parents the bill. This breed of forensic scatology has worked elsewhere, but can it take on London? 

DNA testing dog poo is an idea that’s simple and brilliant. I don’t know who thought of it first but I’m going to blame Stephen Dubner, half of the team behind the Freakonomics books and podcast. Ten years ago, he wrote a fanciful editorial in the New York Times laying out the solution to Manhattan’s significant dog waste problem. It seemed impractical at the time, but now that DNA testing has become cheaper, the idea has caught fire. It’s happening all across the US, has undergone trials in Israel and Singapore, and now it’s coming to the UK.

The technique that’s slated for use in Barking is called PooPrints, patented by a US company that made its name doing canine paternity testing.

Here’s how it works. If you’re the manager of a building or housing community, you get all your residents to provide a sample of their dog’s saliva or blood, and PooPrints puts them into a DNA registry. Then, when a mystery pile appears, you collect a specimen. (There are a few tricks to this. For example, you want to collect from the “outer crust”, because it contains the most cells. Find more tips in this gruesome instructional video!) You send the specimen to the PooPrints CSI team, they compare it against the database, and you can consider this fecal matter…

… settled.

What you do with the information is up to you — some communities levy $100 fines, others do a name-and-shame list. Either way, these programs seem to have been very successful. Many community managers say the errant dog poo supply dries up almost overnight.  

But will this work in a city? Poo DNA testing has succeeded in places where you can be forced to submit your samples, and where violating the rules results in nasty consequences. In the many condominiums and gated communities where this has been deployed in the US, motivation comes in the form of shame and fear of being booted out of your residence.

How will London convince dog owners to swab? Barking, the Guardian reports, plans to introduce legislation to make DNA swabs on dogs mandatory.

Next April, everyone in the UK will have to chip their dog. Darren Rodwell, leader of Barking & Dagenham council, says he hopes “to have a scheme going with local veterinarians where people can get the swab and chip done together”. The council plans to introduce a public space protection order (PSPO) to make DNA testing mandatory.

Mandatory DNA testing for all dogs. And then what? Even if you can force every dog owner in Barking to register their dog with the PooPrints database, you might not get results. After all, shame is not really effective in an anonymous city, and a person who leaves his dog’s poo on the street is already kind of antisocial. So let’s assume the punishment takes the form of a fine. But if you have enough money, you can think of poo fines as the membership fee in an exclusive club whose members can let their dogs crap in the street. The “freakonomic” consequences of PooPrints, then, might be that all street poo is “1 Percent” No. 2.

I wouldn’t want to give the law more teeth than that. Even in authoritarian Singapore, where vandalism will get you caned, leaving your dog’s leavings carries no punishment. In some US residences where PooPrints has been adopted, your dog (and you) can be evicted for repeat offenses. What’s a reasonable noncompliance penalty? You can’t get evicted from Barking. (Presumably.) Should the government take a person’s dog from them because they leave its poo in the street? That seems like overreaching.

One common refrain among communities that have adopted PooPrints is that they barely need to send any samples: like fake surveillance cameras, the mere suggestion that this could be used against them makes people clean up their act.

That raises a different question — just how tried and tested is this technology? Has it survived appeals and second opinions? In his 2005 article, Dubner stood behind poo as a solid source of DNA.

Because stomachs and intestinal walls shed so many cells, poop is in fact a robust DNA source; during a murder trial in Indiana in 2002, the defendant was convicted in large part because the dog poop in his sneaker tread linked him to the scene of the crime.

PooPrints says it has a very low incidence of false positives, thanks to its practice of analysing more markers than the FBI does in its violent crime biometric database. But as a dog owner myself, I can tell you about various deeply unpleasant scenarios in which a poo sample might become cross-contaminated. Like the time my dog got so engrossed in sniffing a street poo that she licked it.

Cross-contamination has tripped up (human) paternity testing in the past, raising questions about accuracy. So the best thing to come out of this Barking endeavour could be a robust, rigorously tested DNA poo test. And of course a way to make its bark match its bite.

Credits:

Poo icon: shutterstock

David Caruso: the internet

Title pun: Erik